[Analysis of a Chinese pedigree with autosomal dominant Charcot-Marie-Tooth disease type 2A2A].

OBJECTIVE: To explore the genetic basis of a pedigree affected with peroneal muscular atrophy. METHODS: Neuroelectrophysiological examination and whole exome sequencing were carried out for the proband, a six-year-and-ten-month-old boy. Suspected variant was verified in his family members through Sanger sequencing. Bioinformatic analysis was carried to predict the conservation of amino acid sequence and impact of the variant on the protein structure and function. RESULTS: Electrophysiological examination showed demyelination and axonal changes of motor and sensory nerve fibers. A heterozygous missense c.1066A>G (p. Thr356Ala) variant was found in exon 11 of the MFN2 gene in the proband and his mother, but not in his sister and father. Bioinformatic analysis using PolyPhen-2 and Mutation Taster software predicted the variant to be pathogenic, and that the sequence of variation site was highly conserved among various species. Based no the American College of Medical Genetics and Genomics standards and guidelines, the c.1066A>G (p. Thr356Ala) variant of MFN2 gene was predicted to be likely pathogenic (PS1+ PM2+ PP3+ PP4). CONCLUSION: The heterozygous missense c.1066A>G (p.Thr356Ala) variant of the MFN2 gene probably underlay the disease in the proband, and the results have enabled genetic counseling and prenatal diagnosis for this family.

[Application of polyetheretherketone rod semi-rigid pedicle screw internal fixation in lumbar non-fusion surgery].

OBJECTIVE: To investigate the effect of Polyetheretherketone (PEEK) rod semi-rigid pedicle screw fixation system in lumbar spine non-fusion surgery. METHODS: A total of 74 patients with tow-level lumbar degenerative diseases who underwent surgery from March 2017 to December 2019 were divided into PEEK rod group and titanium rod group. In the PEEK rod group, there were 34 patients, including 13 males and 21 females, aged from 51 to 79 years old with an average of (62.4±6.8) years old;There were 1 patient of L1-L3 segments, 7 patients of L2-L4 segments, 20 patients of L3-L5 segments and 6 patients of L4-S1 segments. In the titanium rod group, there were 40 patients, including 17 males and 23 females, aged from 52 to 81 years old with an average of (65.2±7.3) years old;There were 3 patient of L1-L3 segments, 11 patients of L2-L4 segments, 19 patients of L3-L5 segments and 7 patients of L4-S1 segments. The general conditions of operation, such as operation time, intraoperative blood loss, postoperative drainage was recorded. The visual analogue scale (VAS) for low back pain and Oswestry disability index (ODI) were compared in preoperatively and postoperatively(3 months, 12 months and last follow-up) between two groups. The change of range of motion (ROM) was observed by flexion and extension x-ray of lumbar. RESULTS: All patients successfully completed the operation. The follow-up time ranged from 22 to 34 months with an average of(26.8±5.6) months. The operative time (142.2±44.7) min and intraoperative blood loss(166.5±67.4)ml in PEEK group were lower than those in titanium group [(160.7±57.3) min、(212.8±85.4) ml](P<0.05). There was no significant differences in postoperative drainage between the two groups (P>0.05). At the final follow-up visit, in PEEK group and titanium group VAS of low back pain[(0.8±0.4) points vs (1.0±0.5) points], VAS for leg pain [ (0.7±0.4) points vs (0.8±0.5) points] and ODI [(9.8±1.6)% vs (12.1±1.5)%] were compared with preoperative [ (5.8±1.1) points vs (6.0±1.1)points], [ (7.2±1.7) points vs (7.0±1.6) points], [(68.5±8.9)% vs(66.3±8.2)%] were significantly different(P<0.05). There was no significant difference in VAS scores between the two groups at each postoperative time point (P>0.05). At 3 months after surgery, there was no difference in ODI between the two groups (P>0.05). There were significant differences in ODI between PEEK group and titanium rod group at 12 months [(15.5±2.1)% vs (18.4±2.4)%] and at the last follow-up [(9.8±1.6)% vs (12.1±1.5)%] (P<0.05). The total range of motion (ROM) of lumbar decreased in both groups after surgery. At 12 months after surgery and the last follow-up, the PEEK group compared with the titanium rod group, the total range of motion of lumbar was statistically significant (P<0.05). The range of motion (ROM) of the fixed segments decreased in both groups after surgery. The ROM of the fixed segments in PEEK group decreased from (9.5±4.6)° to (4.1±1.9)° at the last follow-up (P<0.05), which in the titanium rod group was decreased from (9.8±4.3)°to (0.9±0.5)° at the last follow-up (P<0.05). The range of motion (ROM) of upper adjacent segment increased in both groups, there was statistical significance in the ROM of upper adjacent segment between the two groups at 12 months after surgery and the last follow-up, (P<0.05). There was no screw loosening and broken rods in both groups during the follow-up period. CONCLUSION: The PEEK rod semi-rigid pedicle screw internal fixation system used in lumbar non-fusion surgery can retain part of the mobility of the fixed segment, showing comparable short-term clinical efficacy to titanium rod fusion. PEEK rod semi-rigid pedicle screw internal fixation system is a feasible choice for the treatment of lumbar spine degenerative diseases, and its long-term efficacy needs further follow-up observation.

Review of research on migration, distribution, biological effects, and analytical methods of microfibers in the environment.

Microplastics have been proven to be one of the critical environmental pollution issues. Moreover, microfibers, the most prominent form of microplastics in the environment, have likewise attracted the attention of various countries. With the increase in global population and industrialization, the production and use of fibers continue to increase yearly. As a result, a large number of microfibers are formed. If fiber products are not used or handled correctly, it will cause direct/indirect severe microfiber environmental pollution. Microfibers will be further broken into smaller fiber fragments when they enter the natural environment. Presently, researchers have conducted extensive research in the identification of microfibers, laying the foundation for further resourcefulness research. This work used bibliometric analysis to review the microfiber contamination researches systematically. First, the primary sources of microfibers and the influencing factors are analyzed. We aim to summarize the influence of the clothing fiber preparation and care processes on microfiber formation. Then, this work elaborated on the migration in/between water, atmosphere, and terrestrial environments. We also discussed the effects of microfiber on ecosystems. Finally, microfibers' current and foreseeable effective treatment, disposal, and resource utilization methods were explained. This paper will provide a structured reference for future microfiber research.

[Application of perfusion bone cement screw in lumbar degenerative disease with osteoporosis].

OBJECTIVE: To observe the early clinical effect of perfusion bone cement screw for lumbar degenerative diseases with osteoporosis. METHODS: The clinical data of 28 patients with lumbar degenerative diseases combined with moderate to severe osteoporosis treated by posterior lateral graft fusion with perfusion of bone cement screws from June 2015 to June 2017 were retrospectively analyzed. There were 9 males and 19 females, aged from 55 to 86 years old with an average of 76 years. Anteroposterior, oblique, and dynamic radiography were performed before operation, and the diagnosis was confirmed by CT, MRI and dual energy X-ray absorptionmetry(DXA). All the patients had moderate to severe lumbar spinal stenosis, including 16 cases with degenerative scoliosis, 12 cases with degenerative lumbar spondylolisthesis, and 16 cases with lumbar disc herniation. According to Jikei grade of osteoporosis, 9 cases were grade II and 19 cases were grade III. Visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score were used to assess the improvement of lumbar leg pain, and neurological function. Imaging data were used to observe the circumstance of pedicle loosening, prolapse, breakage and bone cement leakage, and comprehensively evaluate the fusion. RESULTS: The hospital stay was from 10 to 14 days with an average of 12 days; the operative time was 100 to 150 min with an average of 120 min;the blood loss was 200 to 600 ml with an average of 350 ml (for operations more than 3 vertebral segments, blood filtration recovery was intraoperatively used);the postoperative drainage volume was 150 to 600 ml with an average of 300 ml, no allogeneic blood was used in all the patients. Bone cement of 2 to 3 ml were injected into each vertebral body, and bone cement leakage occurred in 2 cases during injection, both of which were paravertebral vessel leakage, and there was no evidence of intravertebral leakage. The injection of bone cement was terminated in a timely manner without serious complications such as nerve injury, bone cement toxicity, and vascular embolization and pulmonary embolism. According to the fusion criteria by X-ray, 18 cases achieved strong bone fusion, and 10 cases were inaccurate fusion, but no pseudarthrosis occurred in the fusion segment. No screw loosening, prolapse or fracture were found, and postoperative VAS, JOA scores were significantly improved. CONCLUSIONS: Perfusion bone cement screw technique can obtain satisfactory effect in treating lumbar degenerative diseases with osteoporosis.

A novel splicing mutation in COL1A1 gene caused type I osteogenesis imperfecta in a Chinese family.

Osteogenesis imperfect (OI) is a heritable connective tissue disorder with bone fragility as a cardinal manifestation, accompanied by short stature, dentinogenesis imperfecta, hyperlaxity of ligaments and skin, blue sclerae and hearing loss. Dominant form of OI is caused by mutations in the type I procollagen genes, COL1A1/A2. Here we identified a novel splicing mutation c.3207+1G>A (GenBank ID: JQ236861) in the COL1A1 gene that caused type I OI in a Chinese family. RNA splicing analysis proved that this mutation created a new splicing site at c.3200, and then led to frameshift. This result further enriched the mutation spectrum of type I procollagen genes.